Question 42927
From 
{{{a/3-1/3=-3}}}

We can calculate the least common multiple of the denominators, to cancel them out later. lcm(3, 1) = 3, so we convert the two sides to a fraction with denominator 3:

{{{(a-1)/3 = -9/3}}}

We cut the denominators out:

{{{a-1 = -9}}}

And solve.
*[invoke linear_equation "a", 1, -1, -9 ]

Therefore, {{{a = -8}}}